You sould put something on it at night!!! Like a brace thingy you know? But yea it hurts because you must not be used to the racket or your pushing yourself to hard!~hahahaha but make sure you keep that good iight it will make you a better player if you know how to take care of these isues! TRUST ME~~~

a doctor ?

What about paying a visit to a doctor ?
The earlier it is treated the better chance to play without this injury...
The worse often for a player is waiting, expecting the injury to surrender...;-P
I did wait once and got my achillis heel broken. It was such a nightmare, I don't wait any longer !